How does GlobalPhone Hosted PBX work?

[mar...@gphone.com]

GlobalTone (GlobalPhone Hosted PBX) is based on Voice over Internet
Protocol (VoIP), a method by which voice is digitized and transmitted
in digital packets rather than using traditional circuit-committed
protocols of the public switched telephone network (PSTN). The IP
concept is similar to the PSTN, except that instead of telephones, it
uses computers, and instead of telephone numbers, every telephone has
a unique IP Address. Thus, IP telephones use IP addresses.

Probably the most significant difference with VoIP, as compared to
PSTN, is that backbone-trunking resources are not assigned in a
dedicated, predictable manner to support a voice call. Instead, trunk
bandwidth for a VoIP telephone conversation is assigned on a random,
as needed basis, via packet switching.

Advanced IP telephony includes many enhanced features, such as voice
mail, conferencing, presentation viewing, and unified messaging for
cell and PDA devices. These service applications reside on hosted
network servers, which deliver very fast response and provide all the
features of GlobalTone.